EMA Has Recommended New Gene Therapy to Treat SMA

31 March 2020

GMP News

EMA has recommended granting a conditional marketing authorisation in the European Union for the gene therapy Zolgensma (onasemnogene abeparvovec) to treat babies and young children with spinal muscular atrophy (SMA), a rare and often fatal genetic disease that causes muscle weakness and progressive loss of movement.

Patients with the disease cannot produce sufficient amounts of a protein called ‘survival motor neuron’ (SMN), which is essential for the normal functioning and survival of motor neurons (nerves from the brain and spinal cord that control muscle movements). Without this protein, the motor neurons deteriorate and eventually die. This causes the muscles to fall into disuse, leading to muscle wasting (atrophy) and weakness.

The SMN protein is made by two genes, the SMN1 and SMN2 genes. Patients with spinal muscular atrophy lack the SMN1 gene but have the SMN2 gene, which mostly produces a ‘short’ SMN protein that cannot work properly on its own. A one-time intravenous administration of Zolgensma supplies a fully functioning copy of the human SMN1 gene enabling the body to produce enough SMN protein. This is expected to improve their muscle function, movement and survival of children with the disease.

Treatment with Zolgensma should only be administered once in suitable clinical centres under the supervision of a physician experienced in the management of patients with SMA.

EMA’s recommendation for conditional marketing authorisation is based on the preliminary results of one completed clinical trial and three supporting studies in patients with spinal muscular atrophy with different stages of disease severity.

The clinical trial providing the main body of data for the assessment of Zolgensma was conducted in 22 patients who were less than six months of age at the time of the gene replacement therapy with Zolgensma.

The survival of patients treated with Zolgensma exceeded what can be expected from untreated patients with severe SMA. Out of 22 patients enrolled in the trial, 20 patients (91%) were alive and did not need permanent ventilatory support at 14 months of age.